Electronic aerosol provision device

ABSTRACT

An electronic aerosol provision system, comprising an air pathway between an air inlet and an air outlet; and a vaporiser for generating vapour into the air pathway; wherein the air pathway between the air inlet and the vaporiser is configured to support laminar airflow.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Phase entry of PCT Application No.PCT/GB2020/050949, filed Apr. 14, 2020, which claim priority to GB1905425.3, filed Apr. 17, 2019, the entire disclosures of which areincorporated herein by reference.

FIELD

The present disclosure relates to an electronic aerosol provisiondevice.

BACKGROUND

A typical electronic aerosol provision device includes an internal airpath which provides a channel between one or more inlets and one or moreoutlets. A user of the electronic aerosol provision device inhales onthe air outlet(s) to create an airflow through the device along thechannel from the air inlet(s) to the air outlet(s).

An electronic aerosol provision device generally also includes a source(precursor) material which is used for forming a vapor or aerosol. Forexample, some devices include a reservoir of liquid and a heater whichis used to vaporize liquid from the reservoir. In other devices, aheater may be used to generate volatiles from a solid material, andthese in turn form a vapor or liquid. In some cases, the liquid or solidmaterial may be provided in a replaceable cartridge. The vapor oraerosol is usually generated in, or migrates into, the channel from theair inlet(s) to the air outlet(s), and is conveyed by the airflow alongthe channel and out through the air outlet(s) for inhalation by a user.

The user experience of such an electronic aerosol provision device isdependent upon the vapor or aerosol that exits the device forinhalation.

SUMMARY

The disclosure is defined in the appended claims.

The approach described herein provides an electronic aerosol provisionsystem comprising an air pathway between an air inlet and an air outletand a vaporizer for generating vapor into the air pathway. The airpathway between the air inlet and the vaporizer is configured to supportlaminar air flow.

The approach described herein provides an electronic aerosol provisionsystem, comprising an air pathway between an air inlet and an airoutlet, a vaporizer for generating vapor into the air pathway, and afacility for adjusting the air pathway to control turbulence within theair pathway.

It will be appreciated that features and aspects of the disclosuredescribed above in relation to the first and other aspects of thedisclosure are equally applicable to, and may be combined with,embodiments of the disclosure according to other aspects of thedisclosure as appropriate, and not just in the specific combinationsdescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the disclosure will now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIG. 1 shows an example electronic aerosol provision system.

FIG. 2 shows an electronic aerosol provision system having a linearairflow channel configured to support laminar airflow according to theapproach described herein.

FIG. 3 shows distributions of aerosol particle sizes generated by anelectronic aerosol provision system such as shown in FIG. 1.

FIG. 4 shows distributions of aerosol particle sizes generated by anelectronic aerosol provision system such as shown in FIG. 2.

FIG. 5 shows an electronic aerosol provision system having a smoothlycurved airflow channel configured to support laminar airflow accordingto the approach described herein.

FIG. 6 shows an electronic aerosol provision system having a facilityfor adjusting the air pathway to control turbulence according to theapproach described herein.

FIG. 7 shows another electronic aerosol provision system having afacility for adjusting the air pathway to control turbulence accordingto the approach described herein.

DETAILED DESCRIPTION

Aspects and features of various examples are described herein. Some ofthese aspects and features may be implemented conventionally and thesemay not be described in detail in the interests of brevity. It will beappreciated that such aspects and features which are not described indetail may be implemented in accordance with suitable conventionaltechniques.

The present disclosure relates to electronic aerosol provision systems,which may also be referred to as electronic vapor provision systems,e-cigarettes, and so on. In the following description, the terms“e-cigarette”, “electronic cigarette”, “electronic aerosol provisionsystem” and “electronic vapor provision system” may be usedinterchangeably unless the context demands otherwise. Likewise the terms“device” and “system” may be used interchangeably, for example, an“electronic aerosol provision system” should be regarded as the same asan “electronic aerosol provision device”, unless the context demandsotherwise. Furthermore, as is common in this technical field, the terms“vapor” and “aerosol”, and related terms such as “vaporize”,“aerosolise”, and “volatilize”, may likewise be used interchangeablyunless the context demands otherwise.

Such electronic aerosol provision systems/devices are often provided inmodular form, for example, comprising a control unit and a cartomizer(the latter being a combination of a cartridge and a vaporizer). Theterm electronic aerosol provision system/device is used herein to denoteone or more modules (such as the control unit) that act (comprisecomponents) to generate an aerosol or vapor. Such a system/device may beconfigured to receive one or more additional modules, for example, amodule (cartridge) containing liquid or other precursor to be vaporized,or may be provided in combination with one or more additional modules.

One common configuration for an electronic aerosol provisionsystem/device having a modular assembly is to comprise a reusable part(the main control unit) and a replaceable (disposable) cartridge part,also referred to as a consumable. The replaceable cartridge part oftencontains the vapor (aerosol) precursor material and may (in someimplementations) also contain a vaporizer (aerosolizer) to form acartomizer. The reusable part often contains a power supply, forexample, a rechargeable battery, and control circuitry for thedevice/system. These parts may contain further components depending onfunctionality. For example, the reusable part may contain a userinterface for receiving user input and displaying operating statuscharacteristics, while the replaceable cartridge part may contain atemperature sensor for helping to control the temperature of thevaporizer.

A cartridge part is usually electrically and mechanically coupled to acontrol unit for use. When the vapor precursor material in a cartridgeis exhausted (fully consumed), or the user wishes to switch to adifferent cartridge having (for example) a different vapor precursormaterial, the cartridge may be removed from the control unit and areplacement cartridge provided in its place. Devices conforming to thistype of two-part modular configuration are sometimes referred to astwo-part devices.

Some of the example devices/systems described herein are based on anelongated two-part device/system that utilises disposable cartridges.However, it will be appreciated that the approach described herein mayalso be adopted for different configurations of an electronic aerosolprovision system/device, for example, single-part devices or modulardevices comprising more than two parts, refillable devices andsingle-use disposable devices. In addition, the approach describedherein may be applied to devices/systems having other geometries (notnecessarily elongate), for example, based on so-called box-mod highperformance devices that typically have more of a box-like shape.

FIG. 1 is a schematic cross-sectional representation of a firstelectronic aerosol provision device 20. The e-cigarette 20 comprises twomain sections, namely a control section 22 and a cartridge section 24.In some implementations, the cartridge section and the control sectionare separate parts which can be detached from one another. In normaluse, the control part 22 and the cartridge part 24 are releasablycoupled together at an interface 26. When the cartridge part 24 isexhausted (after depletion of an aerosol precursor material therein), orthe user wishes to switch to a different cartridge, the cartridge 24 maybe detached from the control part 22. The detached cartridge may then bedisposed of (if fully depleted) and a replacement cartridge coupled tothe control part. Another possibility is that the same cartridge part 24may be refilled and re-attached to the control part 22. In otherimplementations, the cartridge part 24 might be refillable in situ, i.e.while still attached to the control part 22 (in which case the cartridgesection 24 might potentially be permanently attached to the controlsection 22).

The interface 26 generally provides a structural (mechanical),electrical and airflow path connection between the control section 22and the cartridge section 24. For example, the interface 26 may provideappropriately arranged electrical contacts for establishing variouselectrical connections between the two sections. Likewise, the interfacemay support (define) an airflow channel (path) between the two sectionsas appropriate.

It will be appreciated that other implementations of the electronicaerosol provision system 20 may have a different configuration;moreover, different features from different implementations as describedherein may be mixed together as appropriate. For example, in someimplementations, the control section 22 and the cartridge section 24might be fixed together (rather than being detachable); as noted above,this might be the case when the cartridge section 24 is re-Tillable insitu. In some implementations, a vaporizer may be provided in thecontrol section 22 rather than in the cartridge section 24, in whichcase the interface 26 might be configured to support the transfer of avapor precursor (such as a liquid) from the cartridge section 24 to thecontrol section 22—but without necessarily supporting the transfer ofelectrical power from the control section 22 to the cartridge section24. In some implementations, the interface 26 may support a wirelesstransfer of power from the control section to the cartridge section, forexample, based on electromagnetic induction. In this case, a directphysical (electrical) connection between the control section 22 and thecartridge section 24 may not be provided. Furthermore, in someimplementations, the airflow path through the electronic aerosolprovision device 20 might not go through the control section 22, hencethe interface 26 might not include an airflow channel connection betweenthe control section 22 and the cartridge section 24. The skilled personwill be aware of various other potential modifications.

In the example of FIG. 1, the cartridge section 24 comprises a cartridgehousing 62 which may be made of plastic or any other suitable material.The cartridge housing 62 supports other components of the cartridgesection 24 and provides a mechanical interface with the control section22 as part of interface 26. The cartridge section includes an airflowchannel (or pathway) 72 and a mouthpiece 70 which defines an air outlet71 from the airflow channel 72.

Within the cartridge housing 62 is a reservoir 64 that contains a liquidto provide a vapor precursor material; this is often referred to as ane-liquid. The liquid reservoir 64 in the device of FIG. 1 has an annularshape about (around) the airflow channel 72. The shape of the reservoir64 is defined by an outer wall, provided by the cartridge housing 62,and an inner wall that forms the outside or boundary of the airflowchannel 72 through the cartridge section 24. The reservoir 64 is closedat each end to retain the e-liquid, by mouthpiece 70 at the downstreamend of the cartridge section 24 and by the housing 62 forming interface26 at the upstream end.

The cartridge section 24 further comprises a wick (liquid transportelement) 66 and a heater (vaporizer) 68. In the device shown in FIG. 1,the wick 66 extends transversely across the cartridge airflow channel72, i.e. perpendicular to the airflow direction along channel 72. Eachend of the wick is configured to draw liquid from the reservoir 64through one or more openings in the inner wall of the liquid reservoir64. The e-liquid infiltrates the wick 66 and is drawn along the wick 66by capillary action (i.e. wicking). The heater 68 may comprise anelectrically resistive wire coiled around the wick 66, for example anickel chrome alloy (Cr20Ni80) wire, and the wick 66 may comprise aglass fibre bundle or a cotton fibre bundle. Many other options will beapparent to the skilled person; for example, the wick might be made ofceramic, the wick and heater coil might be arranged longitudinallyrather than transversely, there might be multiple heater coils 68, theremight be multiple wicks 66, the heater 68 may have a planarconfiguration, and so on.

During use, electrical power may be supplied to the heater 68 tovaporize an amount of e-liquid (vapor precursor material) drawn to thevicinity of the heater 68 by the wick 66. The vaporized e-liquid thenbecomes entrained in air drawn along the cartridge airflow channel 72towards the mouthpiece outlet 70 for user inhalation. The rate at whiche-liquid is vaporized by the vaporizer (heater) 68 generally depends onthe amount of power supplied to the heater 68, as well as the wicking orliquid transport capacity of wick 66. In some devices, the rate of vaporgeneration (the vaporisation rate) can be adjusted by changing theamount of power supplied to the heater 68, for example through the useof pulse width or frequency modulation techniques. In general, thee-liquid vapor formed by the heater 68 cools in the airflow channel 72and at least partially condenses into particles (small droplets ofliquid), thereby forming an aerosol. It is this aerosol that is theninhaled by a user through mouthpiece outlets 71.

The control section 22 shown in FIG. 1 comprises an outer housing 32with an opening that defines an air inlet 48 for the e-cigarette 20, abattery 46 for providing electrical power to operate the e-cigarette 20,control circuitry 38 for controlling and monitoring the operation of thee-cigarette 20, a user input button 34 and a visual display indicator44. The outer housing 32 is configured to receive the cartridge section24, thereby providing a smooth integration (union) of the two sectionsor parts at the interface 26. For example, the outer housing 32 mayinclude clips or slots or any other suitable engagement features forreceiving corresponding features of the cartridge section 24.

The battery 46 is generally rechargeable such as through a chargingconnector in the control section housing 32, e.g. a USB connector (notshown in FIG. 1). The user input button 34 may be used to performvarious control functions. The display 44 may (for example) comprise oneor more LEDs for displaying information about the charge status of thebattery 46 or any other suitable information or indication. In someimplementations, the user input button 34 and the display 44 may beintegrated as a single component. The control circuitry 38 is suitablyconfigured (programmed) to control the operation of the electroniccigarette, for example to regulate the supply of power from the battery46 to the heater 68 for generating vapor.

The air inlet 48 connects to an airflow path 50 through the controlsection 22. The control part section path 50 in turn connects to thecartridge airflow channel 72 via the interface 26 when the control part22 and cartridge part 24 are connected together. Thus, when a userinhales on the mouthpiece 70, air is drawn in through the air inlet 48,along the control section air path 50, through the interface 26, alongthe cartridge airflow channel 72, and out through the opening of themouthpiece 70 for user inhalation. In the example of FIG. 1, the airflowpath 50 is configured so that the airflow through air inlet 48 isperpendicular to the airflow through the air outlet 71 during a userinhalation. In particular, the air inlet 48 is arranged on a side of theouter housing 32 (rather than the base). Such an air inlet may be termeda side hole. The airflow path 50 incorporates a corner or angle wherebythe airflow during an inhalation transitions sharply from a firstdirection of airflow from the air inlet 48 to the corner to a seconddirection of airflow from the corner to the interface 26. As can be seenin FIG. 1, the second direction of travel is perpendicular to the firstdirection of travel.

FIG. 2 is a schematic cross-sectional representation of a secondelectronic aerosol provision device 200. The components of thee-cigarette 200 of FIG. 2 are generally the same as or similar to thosedescribed in relation to FIG. 1 (and labelled with like referencenumbers), and so these components will not be discussed again. However,in contrast to the first e-cigarette 20 of FIG. 1, which comprises aside hole air inlet 48, the second e-cigarette 200 of FIG. 2 comprisesan air inlet 248 in the base (or bottom) of the e-cigarette (where theorientation of an e-cigarette is defined in the conventional manner suchthat the mouthpiece 71 is at the top). With this location for the airinlet 248, the control section airflow pathway 250 and the cartridgesection airflow pathway 72 are coaxially aligned such that there is astraight air path along the length of the airflow channel. Thus as shownin FIG. 2, the airflow channels 250, 72 of electronic vapor provisiondevice 200 are aligned such that airflow through the device from the airinlet 248 to the vaporizer 68 and then out through the mouthpiece 70follows a substantially straight line (linear) pathway, i.e. heading insubstantially a single direction, without changing direction, curving,bending, etc.

Although FIG. 2 shows one example in which the airflow pathways in thecontrol section 22 and in the cartridge section 24 have a coaxial(co-aligned) configuration, it will be appreciated that such aconfiguration may be achieved differently in other implementations.Furthermore, while e-cigarette 200 is shown as having two modules(cartridge part 24 and control part 22), other implementations with acoaxial configuration for airflow pathways 52 and 72 may be implementedas a one-piece device, or else as a system comprising more than twomodules.

The straight (linear) configuration of the airflow channel 250 throughthe control section 22 in FIG. 2, compared with the angled (cornered)configuration in the airflow channel 50 of e-cigarette 20 in FIG. 1,helps to support a laminar airflow within the channel 250. In a laminarairflow (also referred to herein as a linear airflow), the air generallyall flows in parallel in the same direction. For example, for laminarairflow along a cylindrical pipe, all the air flows in parallel in anaxial direction along the pipe. The airflow velocity along the pipe hasa radial profile according to distance from the centre of the pipe. Theair flowing along the central axis of the pipe flows most quickly, whilethe airflow velocity then gradually drops with radial distance away fromthe centre to a zero velocity adjacent the edge or wall of the pipe in aregion referred to as the boundary layer.

In contrast to laminar flow, the presence of features such as corners,bends, obstructions, etc. along an airflow path generally introducesturbulence into the airflow. This turbulent airflow (also referred toherein as non-linear airflow) is created by, and reflects, localisedvariations in air pressure and other instabilities. For example, airflowing around (but close to) an obstruction may have a higher pressurethan air flowing further away from the obstruction; this may then bebalanced by a region of relatively low pressure immediately after theobstruction. Localised movements of air in effect seek to rebalance theair pressure variations, and thereby introduce turbulence into theairflow.

Note that turbulence may also arise even in an axially aligned channelshown in FIG. 2. For example, if the air is pushed through a pipe tooquickly (i.e. with too great a pressure difference), the high level ofradial shear resulting from different axial velocities at differentradial distances out from the centre of the channel disrupts theairflow, leading to instabilities and other forms of turbulence.

A dimensionless parameter known as the Reynolds number (R) is often usedto characterise the laminar and turbulent flow regimes. The Reynoldsnumber is defined as R=uL/v, where u is the flow speed, v the viscosity,and L is a linear scale size of the flow (this might be the diameter ofa pipe, for example). A low Reynolds number will generally producelaminar flow, while a high Reynolds number will generally produceturbulent flow. The transition between laminar flow and turbulent flowmight typically occur for R in the range 2000-3000 (although thistransition point is typically sensitive to various factors, and may lieoutside the above range in some circumstances). Note that increasing theflow speed increases the Reynolds number, and hence may induce atransition to turbulent flow, as noted above. In contrast, increasingthe viscosity will decrease the Reynolds number; this can be regarded asa higher viscosity damping out turbulent motion.

FIGS. 3 and 4 are graphs showing the frequency distributions of particlesizes produced by the first and second example e-cigarettes, namely theside-hole device 20 of FIG. 1 and the linear flow device 200 of FIG. 2respectively. The particle size refers to the size of particles ordroplets in the vapor or aerosol exiting the device through air outlets71. Each graph shows ten repeated measurements of the particle sizedistribution. Statistical summaries of the frequency distribution of theparticle sizes for each measurement are provided in Tables 1 and 2below.

TABLE 1 “Side-hole” e-cigarette Date - Time File Cv(%) Dx(10) Dx(50)Dx(80)

[V] 4 Dec. 2017 - 16:15:03.0384 171204 Side Hole r1 1.1 1.0014 0.39 1.122.56

[V] 4 Dec. 2017 - 16:15:32.9526 171204 Side Hole r1 1.2 0.0016 0.47 1.282.69

[V] 4 Dec. 2017 - 16:16:02.9672 171204 Side Hole r1 1.3 0.0016 0.63 1.443.00

[V] 4 Dec. 2017 - 16:16:33.0216 171204 Side Hole r1 1.4 0.0020 0.32 1.683.33

[V] 4 Dec. 2017 - 16:17:03.0560 171204 Side Hole r1 1.5 0.0016 0.65 1.503.15

[V] 4 Dec. 2017 - 16:17:33.0904 171204 Side Hole r1 1.6 0.0021 0.92 1.773.33

[V] 4 Dec. 2017 - 16:18:03.1246 171204 Side Hole r1 1.7 0.0016 0.86 1.713.32

[V] 4 Dec. 2017 - 16:18:33.1584 171204 Side Hole r1 1.8 0.0017 0.87 1.703.23    [V] 4 Dec. 2017 - 16:19:03.1926 171204 Side Hole r1 1.9 0.00170.74 1.55 3.08

[V] 4 Dec. 2017 - 16:19:33.2272 171204 Side Hole r1 1.10 0.0017 0.961.81 3.37 [V] = Volume [N] = Number

TABLE 2 “Direct linear flow” e-cigarette Date - Time File Cv(%) Dx(10)Dx(50) Dx(80)

[V] 14 Dec. 2017 - 11:56:39.4 . . . 171214 al bh beta 58 r1 1.1 0.00140.20 0.53 1.36

[V] 14 Dec. 2017 - 11:57:09.3 . . . 171214 al bh beta 58 r1 1.2 0.00110.23 0.62 1.53

[V] 14 Dec. 2017 - 11:57:39.3 . . . 171214 al bh beta 58 r1 1.3 0.00130.22 0.68 1.93

[V] 14 Dec. 2017 - 11:58:09.4 . . . 171214 al bh beta 58 r1 1.4 0.00120.27 0.85 1.24

[V] 14 Dec. 2017 - 11:58:39.4 . . . 171214 al bh beta 58 r1 1.5 0.00120.25 0.76 1.99

[V] 14 Dec. 2017 - 11:59:09.4 . . . 171214 al bh beta 58 r1 1.6 0.00110.23 0.72 2.15

[V] 14 Dec. 2017 - 11:59:39.5 . . . 171214 al bh beta 58 r1 1.7 0.00150.20 0.55 1.56    [V] 14 Dec. 2017 - 12:00:09.5 . . . 171214 al bh beta58 r1 1.8 0.0015 0.22 0.65 1.91

[V] 14 Dec. 2017 - 12:00:39.5 . . . 171214 al bh beta 58 r1 1.9 0.00150.54 1.25 2.41

[V] 14 Dec. 2017 - 12:01:09.6 . . . 171214 al bh beta 58 r1 1.10 0.00140.30 0.97 2.47 [V] = Volume [N] = Number

The final three columns of each Table define parameters of the particlesize distribution for that measurement. Thus in the first line of Table1, Dx(10)=0.39 implies that 10% of the particles have a size less than0.39 microns (μm), Dx(50)=1.12 implies that 50% of the particles have asize less than 1.12 microns (μm) (i.e. this is the median size), andDx(00)=2.56 implies that 90% of the particles have a size less than 2.56microns (μm). A comparison of FIGS. 3 and 4 (and the associated tables)clearly shows that the particle sizes are generally smaller for a directlinear flow e-cigarette (such as shown in FIG. 2) than for a side-holee-cigarette (such as shown in FIG. 1). It is also suggested that thedirect linear flow measurements of FIG. 4 produce a slightly tighter(more compact) distribution than the side-hole measurements of FIG. 3.

Without being bound by theory, it is considered that the laminar(non-turbulent) airflow may form an aerosol having a smaller particlesize than the non-laminar (turbulent) airflow because the turbulencecauses more collisions between aerosol particles, and such collisionsmay lead to coagulation between particles and hence a growth in particlesize. In contrast, when the airflow is laminar, coagulation amongparticles might be reduced since the airflow is substantially all inparallel, aligned with the axial direction. Consequently, there is lessmixing in the airflow, and hence less potential for coagulation. It isalso possible that turbulence brings more vapor into contact withparticles, and hence leads to a faster condensation of vapor onto theparticles (compared with laminar flow), thereby leading to a largerparticles. This faster condensation of vapor onto the existing particlesmay occur in addition to, or in place of, the faster coagulation ofparticles.

It has been found that an enhanced user experience can be achieved by anelectronic vapor provision system that generally provides an aerosolhaving a smaller particle size for inhalation by the user. Without beingbound by theory, this user preference for a smaller particle size mayarise from one or more factors, such as easier absorption of theparticles by tissue, increased lightness or diffusiveness of theparticles, greater uniformity (consistency) of the particles, increasedtravel distance of the particles, etc.

In view of this user preference, the airflow configuration of thee-cigarette 200 of FIG. 2 is advantageous with respect to the airflowconfiguration of the e-cigarette 20 of FIG. 1, because the straightairflow channel 250 of FIG. 2 helps to provide laminar airflow, andhence a smaller particle size, compared with the angled airflow channel50 of FIG. 1. In practice, in many actual devices, the airflow may haveboth laminar and turbulent components. Increasing the proportion oflaminar components at the expense of the turbulent components shouldstill help promote a reduced particle size and hence an improved userexperience. Accordingly, the benefits of providing a laminar flow arenot binary (all or nothing), but rather can be realised by incrementallyincreasing the proportion of laminar flow in a given device.

FIG. 5 is a schematic cross-sectional representation of a thirdelectronic aerosol provision device 500. The components of thee-cigarette 500 of FIG. 5 are generally the same as or similar to thosedescribed in relation to FIG. 1 (and labelled with like referencenumbers), and so these components will not be discussed again. Incontrast to the example e-cigarette 20 of FIG. 1, which comprises a sidehole air inlet 48 with an angled airflow channel 50, and also incontrast to the example e-cigarette 200 of FIG. 2, which comprises anair inlet 248 in the base (or bottom) of the e-cigarette 200 to providea straight line (linear) airflow channel 250, the e-cigarette 500 ofFIG. 5 comprises an airflow pathway 550 in the control section 22 whichis side-opening 548 (like the e-cigarette 20 of FIG. 1), but having asmooth, continuous curve for the airflow channel 550 between the airinlet 548 (side-hole) and the interface 26.

Configuring the airflow pathway 550 to have such a continuous curve,rather than a sharp corner or angle, helps to support laminar air flow.Thus implementing an air pathway 550 which imparts a gradual change indirection of the airflow allows the device to comprise a side-hole butwith a lower level of turbulence (if any), compared with theconfiguration of FIG. 1. An example e-cigarette 500 may therefore havean airflow channel 550 with a radius of curvature greater than 5 mm,greater than 10 mm, or preferably greater than 15 mm, to reduce (oreliminate) turbulence (compared with the configuration of FIG. 1), andso help to reduce particle size in the aerosol provided by the device.

In some implementations, the continuous curve of the airflow channel 550may only extend part-way between the air inlet 548 and the interface 26.For example, the airflow channel 550 may have a smoothly curved portionnear air inlet 548, followed by a linear portion near the interface 26(or conversely, the airflow channel 550 may have a smoothly curvedportion near the interface 26, following on from a linear portion nearthe air inlet 548). More generally, there may be more than onecontinuous curve or more than one linear section in the airflow channel550. A further possibility is that a continuous curve (or multiple suchcurves) might be approximated by a sequence of short linear sections,whereby the change in orientation of between any two successive linearsections is small, for example, in the range of 1-5 degrees, so as tolimit or avoid the introduction of turbulence.

FIG. 6 is a schematic cross-sectional representation of a fourthelectronic aerosol provision device 600. The components of thee-cigarette 600 of FIG. 6 are generally the same as or similar to thosedescribed in relation to FIG. 1 (and labelled with like referencenumbers), and so these components will not be discussed again. Incontrast to the e-cigarettes shown in FIGS. 1, 2 and 5, which have fixedairflow channel configurations, the e-cigarette 600 of FIG. 6 has anairflow pathway 650 which may be modified to change the level ofturbulence in air inhaled through the device. In other words, thee-cigarette 600 of FIG. 6 includes a facility to adjust the air pathwayto control the amount of turbulence within the air pathway, and hence tochange the particle size distribution in the aerosol produced by thee-cigarette 600.

The airflow channel 650 of e-cigarette 600 comprises two sections, afirst movable channel section 610 and a second fixed section 610. Thesetwo sections are joined by an appropriate coupling or connector 615. Thefirst movable airflow channel section 610 therefore extends from the airinlet 648 to the coupling 615, while the second airflow channel section611 extends from the coupling 615 to the interface 26. The movableairflow channel section 610 in effect is able to rotate about thecoupling 615 to reposition the air inlet 648. In particular, theposition of the air inlet 648 can be rotated as indicated by the arrowsbetween position A and position A′. In position A′, the e-cigarette 600approximates the side-hole configuration shown in FIG. 1, while inposition A the e-cigarette 600 approximates the direct linear flow(bottom hole) configuration shown in FIG. 2.

The e-cigarette 600 includes a switch or button 625 for a user to rotatethe movable section 610 between positions A and A′. This switch 625 maybe provided with a suitable mechanical coupling (not shown) toaccomplish this rotation of the movable section 610. Another possibilityis that the rotation of section 610 is performed using electrical powerfrom battery 46 (again under the control of switch or button 625). Otheractuation mechanisms may be implemented, including direct movement by auser of the movable section 610, in which case button/switch 625 mightbe omitted.

Although the e-cigarette 600 has been described above as having twooperational positions for movable section 610 corresponding to A and A′(so that the position shown in FIG. 6 is transitional between these twooperational positions), other implementations may have one or moreadditional operational positions intermediate A and A′. Someimplementations may allow a continuous adjustment, i.e. the movablesection 610 can be located at any desired position intermediate A andA′. It will be appreciated that the portion 621 of the control sectionhousing 32 in which air inlet 648 is formed will be arranged toaccommodate the desired range of positions for the air inlet 648.

By moving the position of the air inlet 648 from position A to positionA′ (through any supported intermediate positions) an increasing level ofturbulence can be imparted to the airflow—which as described above, willgenerally result in an aerosol having a larger particle size. Thisprovides users with control over a parameter (particle size) which has adirect physical impact on their experience of using the e-cigarette 600.In particular, different particle sizes (large or small) may bepreferred by different users, or for different cartridges, differente-liquids, or just in different user circumstances. The use of button625 to control the position of air inlet 648 by moving section 610 toadjust turbulence provides users with a control over aerosol particlesize according to their specific preferences and circumstances.

For example, in a first orientation, as indicated by position A, themovable channel section 610 is co-aligned with the remainder of theairflow channel 650, in particular fixed section 611, and so turbulenceis minimised. In a second orientation, as indicated by position A′, themovable channel section 610 is now perpendicular to the remainder of theairflow channel 650 and so turbulence is introduced (or increased). Notethat this mechanism allows the level of turbulence to be altered withlittle or no change to the overall flow rate. In particular, the size ofthe air inlet 648 and hence the amount of air inhaled during a puff issubstantially maintained regardless of the orientation of the movablechannel section 610, however, the particle size distribution for thepuff is dependent on (and controlled by) the location setting of themovable channel section 610.

As described above, the orientation of the movable airflow section 610may be selected by a user interacting with the device through amechanical switch 625 or similar device such as a wheel or lever toallow the user to tailor the particle size to his/her particularpreference. In some implementations, this adjustment of the movableairflow section 610 may be performed using the user input button 34 orthe visual display indicator 44 (in place of, or additionally to, usingswitch 625). The changes to the orientation may be performed veryquickly, for example during or between puffs (activations of the heater68), thereby allowing the user to quickly adjust the particle size to adesired setting. A further possibility is that in some circumstances atleast, the orientation of the movable channel section 610 may beautomatically performed by the control circuitry 38, for example, afterrecognising that a particular cartridge 24 containing a particulare-liquid has been attached to the control unit 22.

FIG. 7 is a schematic cross-sectional representation of a fifthelectronic aerosol provision device 700. The components of thee-cigarette 700 of FIG. 7 are generally the same as or similar to thosedescribed in relation to FIG. 1 (and labelled with like referencenumbers), and so these components will not be discussed again. Moreparticularly, the e-cigarette 700 of FIG. 7 has a configuration which isvery similar the e-cigarette 200 of FIG. 2, but further includes, likethe e-cigarette 600 of FIG. 6, a facility to adjust the particle sizedistribution in the aerosol produced by the e-cigarette 700.

Thus as shown in FIG. 7, e-cigarette 700 comprises a fixed airflowpathway 750 extending to air inlet 748 using a direct linear flowconfiguration, the same as for e-cigarette 200 as shown in FIG. 2.However, the e-cigarette 700 further includes a mechanism 715 (shown inschematic form in FIG. 7) to alter the configuration of the air pathway750 so as to modify the relative proportion of laminar and turbulentairflow within the air pathway 750, thereby providing some control overthe resulting particle size distribution of the aerosol produced by thee-cigarette 700. The mechanism 715 may be operated by a user via buttonor switch 725 in a similar manner to the use of button 625 ine-cigarette 600 to move the airflow channel section 610. Likewise, theoperation of mechanism 715 might be performed using the user inputbutton 34 or the visual display indicator 44 (in place of, oradditionally to, using switch 725) or at least partly automatically bythe control circuitry 38.

One implementation of mechanism 715 is a shaped diaphragm or aperturewhich may be changed, for example, between a simple circular shape forthe opening to a star shape (or any other more complex shape) for theopening. The circular shape introduces relative little turbulence, andhence supports a higher proportion of laminar flow, whereas the morecomplex (detailed) star-shaped aperture tends to introduce moreturbulence by creating more localised variations in pressure, and soleads to a lower proportion of laminar flow. The switching between thedifferent aperture shapes may be actuated, for example, using button orswitch 725.

In other implementations, a wall feature, such as a baffle, fin or otherobstruction (or multiple such items) may be moved into or out of theairflow path 750. Inserting such a feature can again lead to morelocalised pressure variations that promote the formation of turbulence.Accordingly, the level of turbulence (and hence the resulting particlesize) may be controlled by adjusting the extent of the insertion orextraction of such obstructions into the airflow channel 750 (e.g. byusing button or switch 725). A similar effect could be achieved, forexample, by forming or flattening surface texture or other topology onthe inside walls of the airflow channel 750.

Another potential implementation of mechanism 715 comprises a grill,grating or other similar structure, which may be moved into the airflowpath 750 to increase the turbulence of the airflow. Typically thegrating is formed of fine wire, or similar, such that the grating actsto disrupt and impart turbulence to the airflow, but does not inhibitthe airflow rate. In some implementations, the grill 715 may bepermanently located in the airflow path 750, however, the configurationor some other property (or properties) of the grill might be varied,such as the size of individual openings within the grill, to change theamount of turbulence produced in the airflow. A further example ofmechanism 715 is an airflow divider, which may be positioned in theairflow path 750 to divide the airflow channel into two or moresubchannels. Both the separation of the airflow into the multiple airchannels, and then the subsequent recombination of the airflow into asingle channel, may lead to the formation of turbulence in the airflow.By varying the proportion of air in each component, the level ofturbulence may be controlled.

In some implementations, the mechanism 715 may not only impact therelative proportion of laminar to turbulent flow, but also the rate ofairflow through the e-cigarette for a given pressure drop or strength ofinhalation—in effect, increasing the resistance to draw (RTD). Forexample, introducing fins or other obstructions into the airflow willgenerally act as additional RTD resistance to the airflow, in additionto increasing the amount of turbulence. It may be desirable however toallow a user to control the amount of turbulence (and hence particlesize) while making little or no change to the RTD (and hence to theoverall flow rate). One way of achieving this is for the e-cigarette toinclude a restrictor somewhere along the overall airflow path which isthe primary restriction on the airflow through the e-cigarette. In sucha configuration, any changes in RTD caused by different settings of themechanism 715 will have a relatively low impact on the overall RTDexperienced by a user. Another approach is for the different settings ofthe mechanism 715 to be designed to alter the amount of turbulence, butnot the overall airflow resistance. For example, for the implementationdiscussed above using a circular aperture to reduce turbulence and astar-shaped aperture to increase turbulence, the sizes of the circularand star-shaped apertures may be arranged so as to provide the sameairflow resistance (RTD contribution) for both apertures.

Although mechanism 715 is shown in FIG. 7 as implemented in the middleof airflow channel 750, it may instead be implemented at the air inlet748 or the interface 26, or at any suitable location between the airinlet 748 and the interface 26. In some implementations, the mechanism715 may comprise multiple components at various locations along the airpathway 750. Alternatively, the mechanism 715 may stretch along asubstantial portion (e.g. most or all) of the airflow channel 750between the air inlet 748 and the interface 26. Furthermore, while theair pathway 750 shown in FIG. 7 is substantially linear (a straightline), other implementations may have a curved air pathway, for example,similar to the shape shown in FIG. 5 for e-cigarette 500.

As described above, the present approach provides an electronic aerosolprovision system or device comprising: an air pathway between an airinlet and an air outlet; and a vaporizer for generating vapor into theair pathway. The air pathway between the air inlet and the vaporizer isconfigured to support laminar airflow.

It has been found that such a laminar airflow can lead to smalleraerosol particles exiting the electronic aerosol provision system, whichin turn can lead to a more favourable user experience. It is believed(without limitation) that a laminar airflow may produce a smallerparticle size by reducing particle coagulation or by reducing vapordeposition onto particles. Although these physical effects generallyhappen downstream of the vaporizer, it is difficult to quiesce anairflow within the electronic aerosol provision system which is alreadyturbulent. Accordingly the approach described herein seeks to prevent orreduce the formation of turbulence upstream of the vaporizer, which thenhelps to prevent or reduce turbulence at (and downstream of) thevaporizer.

An ideal device might have laminar (non-turbulent) airflow along theentire airflow pathway within the device, from air inlet to air outlet.However, it may be difficult in practice to achieve completely laminarairflow within the device, rather the air pathway between the air inletand the vaporizer may be configured to support substantially (mostly)laminar airflow, for example, having at least 60%, 75%, 85%, 90% or 95%of the airflow through the electronic aerosol provision device beinglaminar.

There are various ways in which the air pathway, at least between theair inlet and the vaporizer, may be configured to support (mostly)laminar airflow. For example, the air pathway may comprise a linear(straight line) channel between the air inlet and the vaporizer; theabsence of sharp bends or angles facilitates laminar flow. In some casesthe air pathway between the air inlet and the vaporizer may include oneor more curved portions; each of the one or more curved portions mayhave a radius of curvature greater than 5 mm and preferably greater than15 mm. Again, the provision of gentle curves rather than sharp bends orangles facilitates laminar flow (and also gives more flexibility in theoverall geometry of the device compared with having a straight lineairflow). Laminar flow along the air pathway between the air inlet andthe vaporizer may be further facilitated by ensuring this pathway issubstantially free of (i) obstructions, for example, protrusions,grills, narrow apertures, etc., or (ii) topology for the walls of theair pathway, for example, surface texturing or other features, thatwould introduce turbulence into airflow along the air pathway. It willbe appreciated that a similar approach may be adopted for the portion ofthe air pathway downstream of the vaporizer in order to reduce orprevent turbulence in this downstream portion.

The present approach also provides an electronic aerosol provisionsystem (e.g. such as described above) which comprises a facility tocontrol turbulence within the air pathway. In some implementations, thefacility provides at least first and second settings, the first settingproviding an airflow with a higher proportion of laminar flow relativeto turbulence than the second setting. As noted above, the first settingwill generally therefore produce an aerosol having a smaller particlesize than the second setting. For example, the first setting may producean aerosol having a median particle size (e.g. based on diameter) thatis at least 10%, preferably at least 20%, smaller than the medianparticle size of an aerosol produced by the second setting, or the firstsetting produces an aerosol having a median particle size less than 1micron and the second setting produces an aerosol having a medianparticle size greater than 1 micron. (It will be appreciated that theseratios/sizings are given by way of example only, since they areinfluenced by additional factors, such as the nature of the vaporizer).

It will be appreciated that while some devices may have just twosettings of the facility, other devices may have more settings;furthermore some devices may support a continuous range of settingsbetween upper and lower limits. In general, the facility may be operatedby a user to control turbulence by selecting an appropriate setting,such as by actuating a button or slider, or touching a touch-sensitiveinput device. In this way, a user can select a setting that providesthem with the most satisfactory user experience. In other cases, thefacility might be alternatively (or additionally) operated on anautomatic basis. For example, the device might detect that a particularcartridge or cartomizer has been installed, and set the facility toprovide the most appropriate turbulence level for this cartridge.

There are various ways in which the facility may be implemented. Forexample, in some cases the facility might support movement of theairflow pathway such as to introduce or remove a linear channel betweenthe air inlet and the vaporizer. Other ways of changing the turbulencelevel might be to use a (re)movable airflow divider to divide a portionof the air pathway into two or more channels; a variable aperture (orapertures) along the pathway; or one or more structures that can beintroduced into or altered within the air pathway. Note that thefacility might utilise multiple different approaches for changing thelevel of turbulence.

In some implementations, the facility is arranged to maintain asubstantially constant airflow through the air pathway as the facilityprovides different levels of turbulence. For example, the facility mayuse a smooth (circular) aperture to reduce turbulence, or a more angledaperture, e.g. a star, to increase turbulence. The overall size of eachaperture may then be configured such that the differently shapedapertures provide the same resistance to draw (and hence overallairflow). In this way, a user is able to adjust the particle size of theaerosol without also changing other parameters of the device, such asresistance to draw, which supports easier device management for a user.

In order to address various issues and advance the art, this disclosureshows by way of illustration various embodiments in which the claimeddisclosure may be practiced. The advantages and features of thedisclosure are of a representative sample of embodiments only, and arenot exhaustive or exclusive. They are presented only to assist inunderstanding and to teach the claimed disclosure. It is to beunderstood that advantages, embodiments, examples, functions, features,structures, or other aspects of the disclosure are not to be consideredlimitations on the disclosure as defined by the claims or limitations onequivalents to the claims, and that other embodiments may be utilisedand modifications may be made without departing from the scope of theclaims. Various embodiments may suitably comprise, consist of, orconsist essentially of, various combinations of the disclosed elements,components, features, parts, steps, means, etc. other than thosespecifically described herein, and it will thus be appreciated thatfeatures of the dependent claims may be combined with features of theindependent claims in combinations other than those explicitly set outin the claims. The disclosure may include other embodiments notpresently claimed, but which may be claimed in future.

1. An electronic aerosol provision system, comprising: an air pathwaybetween an air inlet and an air outlet; and a vaporizer for generatingvapor into the air pathway; wherein the air pathway between the airinlet and the vaporizer is configured to support laminar airflow.
 2. Theelectronic aerosol provision system of claim 1, wherein the air pathwaycomprises a linear channel between the air inlet and the vaporizer. 3.The electronic aerosol provision system of claim 1, wherein the airpathway between the air inlet and the vaporizer includes one or morecurved portions, wherein each of the one or more curved portions has aradius of curvature greater than 5 mm and preferably greater than 15 mm.4. The electronic aerosol provision system of claim 1, wherein the airpathway between the air inlet and the vaporizer is substantially free ofobstructions that would introduce turbulence into airflow along the airpathway.
 5. The electronic aerosol provision system of claim 1, whereinthe air pathway between the air inlet and the vaporizer is defined byone or more walls that are substantially free of topology that wouldintroduce turbulence into airflow along the air pathway.
 6. Theelectronic aerosol provision system of claim 1, wherein the air pathwaybetween the vaporizer and the air outlet is configured to supportlaminar air flow.
 7. The electronic aerosol provision system of claim 1,further comprising a facility to control turbulence within the airpathway.
 8. The electrical aerosol provision system of claim 7, whereinsaid facility has at least first and second settings, the first settingproviding a higher proportion of laminar flow relative to turbulencethan the second setting.
 9. The electrical aerosol provision system ofclaim 8, wherein the first setting produces an aerosol having a smallerparticle size than the second setting.
 10. The electrical aerosolprovision system of claim 9, wherein the first setting produces anaerosol having a median particle size that is at least 10%, preferablyat least 20%, smaller than the median particle size of an aerosolproduced by the second setting.
 11. The electrical aerosol provisionsystem of claim 9, wherein the first setting produces an aerosol havinga median particle size less than 1 micron and the second settingproduces an aerosol having a median particle size greater than 1 micron.12. The aerosol provision system of claim 8, wherein the first settingreduces particle coagulation compared to the second setting.
 13. Theaerosol provision system of claim 8, wherein the first setting reducesvapor deposition onto particles compared to the second setting.
 14. Theelectronic aerosol provision system of claim 7, wherein the facilitysupports movement of the airflow pathway.
 15. The electronic aerosolprovision system of claim 14, wherein the movement of the airflowpathway is configured to introduce or remove a linear channel betweenthe air inlet and the vaporizer.
 16. The electronic aerosol provisionsystem of claim 7, wherein the facility comprises an airflow divider fordividing a portion of the air pathway into two or more channels.
 17. Theelectronic aerosol provision system of claim 7, wherein the facilitycomprises an aperture having multiple shapes.
 18. The electronic aerosolprovision system of claim 7, wherein the facility comprises one or morestructures that are introduced into or altered within the air pathway.19. The electronic aerosol provision system of claim 7, wherein theelectronic aerosol provision system is configured to maintain asubstantially constant airflow through the air pathway as the facilityprovides different levels of turbulence.
 20. The electronic aerosolprovision system of claim 7, wherein the facility can be set by a userto control turbulence.
 21. An electronic aerosol provision system,comprising: an air pathway between an air inlet and an air outlet; avaporizer for generating vapor into the air pathway; and a facility foradjusting the air pathway to control turbulence within the air pathway.22. A method of operating an electronic aerosol provision system,comprising: providing an air pathway between an air inlet and an airoutlet and a vaporizer for generating vapor into the air pathway; andadjusting the air pathway to control turbulence within the air pathway.